A high pressure or high temperature fluid maintained within or flowing through a container may exert considerable force on the container. Thus, a container must not only be chemically compatible with the fluid, but it must also have sufficient structural strength to withstand forces due to high pressures or temperatures.
Conventional containers made entirely from a plastic material may be unusable. While plastics may be very inert and, therefore, would not chemically react with the fluid, many plastics stretch or elongate unduly under increased pressure or temperature. This can create structural weaknesses in the container.
Conventional containers made entirely from metal may also be unusable. While metals may have sufficient structural strength to withstand the forces exerted by the fluid, most metals chemically react with fluids such as strong acids or agressive solvents. This can damage the container and contaminate the fluid.
Conventional containers combining metal and plastic materials may be unusable. These containers may have a plastic liner welded to the inside of a metal tank. As the pressure or temperature of the fluid increases, the plastic liner may be forced to expand but have no room for expansion within the rigid metal tank. This can cause the plastic liner to buckle within the tank, creating structural weaknesses in the container and potentially blocking the flow of fluid through the container.